Build NaCl in the CrOS GN builds and make sure "all" works

build/config/features.gni

 # Copyright 2014 The Chromium Authors. All rights reserved.
 # Use of this source code is governed by a BSD-style license that can be
 # found in the LICENSE file.
 
 # This file contains Chrome-feature-related build flags (see ui.gni for
 # UI-related ones). These should theoretically be moved to the build files of
 # the features themselves.
 #
 # However, today we have many "bad" dependencies on some of these flags from,
 # e.g. base, so they need to be global to match the GYP configuration. Also,
@@ skipping 21 matching lines @@
   # TODO(GYP): Get NaCl linking on other platforms.
   # Also, see if we can always get rid of enable_nacl_untrusted and
   # enable_pnacl and always build them if enable_nacl is true.
   # The "is_nacl" part of the condition is needed to ensure that
   # the untrusted code is built properly; arguably it should be
   # guarded by "is_nacl" directly rather than enable_nacl_untrusted, but
   # this will go away when Mac and Win are working and we can just use
   # the commented out logic.
   # Eventually we want this to be:
   #   enable_nacl = !is_ios && !is_android && !is_chromecast
-  enable_nacl = (is_mac || (is_linux && !is_chromeos) || is_nacl) &&
-                current_cpu != "mipsel" && !is_chromecast
+  enable_nacl = (is_linux || is_mac || is_nacl) && current_cpu != "mipsel" &&
+                !is_chromecast
   enable_nacl_untrusted = enable_nacl
   enable_pnacl = enable_nacl_untrusted
 
   # If debug_devtools is set to true, JavaScript files for DevTools are stored
   # as is and loaded from disk. Otherwise, a concatenated file is stored in
   # resources.pak. It is still possible to load JS files from disk by passing
   # --debug-devtools cmdline switch.
   debug_devtools = false
 
   # Enables WebRTC.
@@ skipping 142 matching lines @@
 use_gconf = is_linux && !is_chromeos && !is_chromecast && !is_headless
 
 # Whether to back up data before sync.
 enable_pre_sync_backup = is_win || is_mac || (is_linux && !is_chromeos)
 
 # Enable WebVR support by default on Android
 # Still requires command line flag to access API
 enable_webvr = is_android
 
 use_gio = is_desktop_linux && !is_headless